NBC’s ‘Dateline: Mystery at Chalk Creek’ chronicles the peculiar circumstances surrounding the death of 47-year-old Nancy Mason during her fatal fishing trip in Chalk Creek, Colorado, in late May 2004. With a growing sense that her death might have been staged to look like an accident, Chaffee County investigators found themselves unraveling a web of suspicions that pointed toward a possible murder. If you’re interested in discovering more, including the alleged killers’ identities, here’s what we know.
How Did Nancy Mason Die?
The show noted how her loved ones remembered Nancy Mason for three defining traits — her fondness for parties, her nurturing nature, and her love for reading, especially the Nancy Drew series. Despite her affinity for detective novels, Nurse Nancy inspired her to become a neonatal nurse on the night shift, caring for premature infants. Leading an ordinary American life, she married her first boyfriend, Todd, and they had three sons. The family shared a fiery passion for hockey, spending weekends at Denver’s ice rinks.
However, Nancy’s sporting enthusiasm was limited to the spectator’s role, preferring to enjoy her books. Her youngest child, Wes Linville, recounted, “Mom would go with us to go fishing, but she had a lawn chair and a book.” Her meticulousness as a mother was exemplified through her detailed scrapbooks capturing holidays, vacations, and cherished memories. However, a painful event shattered the family’s unity in 2002 when Todd, a wealthy probate attorney, abruptly left after 26 years of marriage.
Their oldest son, Matt Linville, recalled, “It was horrible, and it was all my dad’s decision. He was done with that part of his life.” The decision devastated Nancy as she slipped into a deep depression that contrasted sharply with her typically upbeat demeanor. Matt narrated the turmoil caused by their biological father’s departure, emphasizing the family’s struggle to cope with the unexpected loss. Nancy’s parents — Bill and Miriam Gaede — recalled her constant tears, illustrating the emotional toll inflicted by the breakup.
Yet, Nancy’s intrinsic kindness and commitment to her children remained despite her inner turmoils. She joined a divorce recovery group at her church and began healing. There, she met Dan Mason, a vibrant and supportive man who provided the companionship she craved. Despite skepticism from her family, including Wes, Nancy married him in a fleeting Vegas ceremony financed by her divorce settlement. The wedding came with a package deal — she accommodated Dan’s friend, Efren Gallegos, into their lives as he moved in with them.
Six months into the November 3, 2003, marriage, the trio — Nancy, Dan, and Efren, embarked on a fishing trip to the canyons around Salida, Colorado, on Memorial Day weekend. Despite being unenthusiastic about hiking, she joined her husband and his friend along the old gold miners’ trails out past the ghost town of St. Elmo in Chaffee County on May 30, 2004. According to the show, Judy and Lynn Cleveland were enjoying an ATV ride on the Memorial Sunday afternoon on the dirt road between their family’s weekend cabin and the old ghost town.
The couple encountered Dan and Efren, distraught and seeking help, as they claimed Nancy had been injured and fallen into the creek. Due to cell phone services being unavailable, the Clevelands led the former to their cabin to call 911. Emergency responders responded, found Nancy’s body by the creek, and pronounced her dead at the scene. An autopsy showed that the cause of death was a broken neck and a severe head injury caused by the 10-foot fall from the cliff into the stream, and her death was initially ruled an accident.
Who Killed Nancy Mason?
Chaffee County authorities initially treated Nancy’s death as a routine incident, considering her lack of experience in hiking and the prevalent river accidents in the area. However, Dan’s behavior raised questions among her family. He acted strangely, appeared uninvolved in funeral planning, and was evasive about discussing the circumstances of her death. Moreover, Dan refused to discuss anything with Nancy’s sons but handed each of them an envelope with a note indicating they should leave him alone while he grieved.
The situation worsened when they found Dan had collected more than $150,000 from Nancy’s life insurance policies, while her three sons were left to split $54,000 among themselves. A month before her death, Nancy had allegedly signed a new will that left everything to Dan, even specifying that her sons were not provided for, with misspellings of their names. While Nancy’s family didn’t legally challenge the will, her sons were left disheartened and suspicious about the circumstances surrounding their mother’s estate.
Matt explained, “With new people getting married, I’m sure she would have changed her will but never taken out her kids, never specifically naming her kids out of the will, and our names misspelled on top of that.” Despite initial assumptions of a tragic accident, the sons suspected Nancy’s death might not have been accidental. Questions surfaced regarding whether the second-time-around newlyweds had been content or if tensions had been simmering within the household.
The show noted how a few alarming incidents painted a different picture of Dan and the dynamics within the marriage. Nancy had reportedly expressed her frustration with Efren’s constant presence in their lives, leading to speculation about domestic conflicts. However, Nancy’s parents were unwilling to entertain the idea of foul play. Miriam stated, “We didn’t like him very well. But, we believed his story.” However, the new investigators assigned to the case were not so trusting as they discovered several inconsistencies in Dan and Efren’s versions.
The investigators claimed the positioning of Nancy’s fishing pole and the peculiar route they had taken to seek help after the incident raised suspicions. The sheriff’s office staged an accident recreation using a dummy to replicate the conditions of Nancy’s fall. The experiment concluded the body should have been found at a different location if she fell accidentally. The detectives noted Dan inherited roughly $300,000 from Nancy’s death and executed a search warrant in January 2005 to search the Mason residence.
The officers located hard drives that revealed internet searches about escort services and a Yahoo search about “people-plus-poison” and “silent weapons” around two weeks before Nancy’s death. The detectives also claimed it was suspicious both men left an injured Nancy to get help and took the longer, desolate route instead of the shortcut to St. Elmo — a crowded tourist spot. Hence, they interviewed Janet Kiddy, Dan’s former wife of 12 years, who alleged he regularly abused her during their marriage and had a permanent restraining order against him.
Despite the simmering suspicions, the case turned cold until the state held a coroner’s inquest in May 2009. Almost five years later, the coroner’s jury issued a new death certificate declaring Nancy, the victim of a homicide. The authorities issued arrest warrants for Dan and Efren, who had since then shifted together in a Dallas, Texas, apartment complex. While the police arrested and extradited Efren, then 33, they could not locate Dan, then 53. Nevertheless, the district attorney did not pursue the case, citing a lack of evidence, and the charges were dropped.